EP1759958B1 - Impact absorbing component for a vehicle structure or for the chassis of a motor vehicle - Google Patents

Description

The invention relates to a crashrelevantes component of a vehicle structure or a chassis of a motor vehicle having the features in the preamble of claim 1.

In the front or Hinterivivagenbereich a motor vehicle are especially in connection with crashrelanten structural and chassis parts complicated designed metal castings used. The use of cast components made of aluminum, aluminum alloys or other suitable cast materials enables high weight savings while at the same time realizing complex structures.

Due to the required in the front of the car impact resistance, it has hitherto been necessary to couple the relatively thick-walled and unyielding cast components with thin-walled deformation components, for example by welding an extruded profile. The production cost for the connection of cast components with an intermediate deformation component is considerable, important, since several items must be made separately, handled, positioned and welded together. Due to the warping caused by welding heat, numerous functional surfaces and holes can only be machined to allowable tolerances after assembly. Even after the mechanical processing such a constructed component is prone to failure and requires a special transport protection.

From the EP 1 541 424 A1 is a crash element, in particular for a motor vehicle in the form of a hollow profile, which has at least one circumferential region in which the hollow profile wall has a, essentially jumping sleeve / step-like offset and wherein the offset is designed as a predetermined breaking point, which in a crash in a breaks up predetermined crash force. The resulting in the event of a crash hollow profile parts are energy absorbing and telescopically inserted into each other in the region of the offset. This crash element is produced by hydroforming a hollow section blank.

On this basis, the invention has the object to show a crashrelevantes component of a vehicle structure or a chassis of a motor vehicle, which is inexpensive to produce and at the same time meets the required crash characteristics.

This object is achieved with a structural component having the features of patent claim 1.

Advantageous developments of Erfndungsgedankens are the subject of the dependent claims.

A very essential feature of the structural component according to the invention is that the deformation element does not have to be welded between the metal casting components, but is produced in one piece, ie monolithically with them in a casting process. This considerably reduces the number of components. It eliminates a costly separate production, positioning and of course the previously required connection process, the is called welding. As a result of the omission of the welding heat, less distortion also occurs in the structural component.

The decisive factor is that the deformation component is able to fulfill the required crash properties. This is achieved in that a plurality of funnel-shaped wedge body arranged in series are provided, which are connected via predetermined breaking webs with the respective adjacent wedge bodies. The wedge bodies are matched in their diameters to one another such that they are telescopically delimited when they reach a limit load while destroying the breakaway webs. As a result, they jam together pushed wedge body self-locking, so that after the breaking of a predetermined breaking web, the first metal casting component is connected with sufficient certainty with the second metal casting. The funnel-shaped design of the wedge body allows self-centering of the adjacent wedge body, so that the metal casting components occupy a predetermined position despite a change in their relative position even in a crash. The self-locking of the wedged together wedged body prevents unintentional release of the metal casting components from each other. With the invention, it is possible to provide a structural component or chassis part produced entirely by casting, which on the one hand is weight-optimized and constructed in accordance with the requirements, but which furthermore has the ability to convert crash energy into deformation energy.

The self-locking can be improved in particular by the fact that the mutually facing surfaces of the abutting walls of the wedge body at least partially have a surface structure which deforms when pushed into each other by mutual friction. Due to the casting technology used, relatively high surface roughness results. These flow as an essential parameter in the determination of pitch angle, wall thickness and dimensioning of the predetermined breaking webs, so that in a given tolerance corridor optimum energy absorption by deformation and friction at a given length reduction occurs. Under surface structure in the context of the invention, not only the casting-related surface roughness are to be understood, but also additional formations, such as small ribs or webs, which interlock and ensure solely that the nested wedge body are clamped together. In particular, the surfaces may have a geometry that causes a twist, that is, a rotation about the longitudinal axis of a wedge body. Due to the mutual rotation pulling apart with rectilinear motion is excluded, so that the wedge body are still securely held together.

The advantages of the invention come into play, in particular, when the component is structural components or chassis parts extending in the vehicle longitudinal direction. In this case, the deformation element also extends in the vehicle longitudinal direction and can absorb the present in particular from the front impact force to some extent. The deformation element shortens in a crash by a predetermined length with simultaneous energy absorption and, above all, while maintaining the load-bearing capacity after the crash.

It is also possible within the scope of the invention for the deformation component to be arranged at a suitable transverse angle to the vehicle longitudinal direction, in particular at a transverse angle of 45 ° to 135 °, in particular 90 °. As a result, the deformation element can also be used in side-impact-relevant areas of the motor vehicle.

For the energy absorption of the deformation element, besides the choice of material, the following parameters are of particular importance: pitch angle, wall thickness, dimensioning of the predetermined breaking rings and surface roughness or surface geometry.

In order to achieve self-locking, it is provided that the mutually facing surfaces of the walls of the wedge bodies which come into abutment against one another have mutually matched pitch angles. If the pitch angle is too large, the deformation component after the crash would not be able to serve as a structural component. Although a too small dimensioned pitch angle leads to safe self-locking, but this increases the overall length of the deformation unit. Essential in the selection of the pitch angle is therefore to find the optimum between safe self-locking and minimum length.

Important for ensuring the support function is that the wedge body is not destroyed in a crash. Only the breaking ridges should break. Their resilience is therefore chosen so that they reach a chosen maximum measured in the circumferential direction tensile and compressive stress in the wedge body to be destroyed. The breakaway rings are therefore designed so that they break with appropriate reserve against material breakage of the wedge body. The load capacity of the breakaway webs is also set so that they break according to the order of the wedge body. This means that with increasing force, the predetermined break rings break one after the other and not at the same time. After breaking a predetermined breaking ring, the previously connected wedge bodies slide telescopically to a limited depth. Already hereby an adjustable energy absorption takes place. When a maximum penetration depth has been reached, the subsequent breakaway web breaks. This process continues until all predetermined break webs are broken and all wedge body abut each other. The maximum penetration depth can also be equated to a maximum force level.

The adaptation of the deformation component to the cast components takes place via adapter pieces. In an adaptation piece, the transition of the geometry of the metal casting component to the geometry of the wedge piece takes place. Also, the adaptation pieces are integrally connected by casting technology with the wedge bodies and the respectively connected cast component.

Due to the cascaded arrangement of the wedge bodies and due to the different load levels that each wedge body has to accommodate or transmit, the wall thicknesses of the wedge bodies may be sized differently. In particular, the wall thickness of a wedge body whose breaking point web breaks first, smaller than the wall thickness of the subsequent wedge body. The wall thickness itself can be constant over the longitudinal extension of the wedge body, but it can also increase in the direction of its funnel-shaped extension. This is expedient because the smaller diameter, inner wall portion is compressed, while the larger-diameter wall portion is pushed when pushing inside from the inside out. The adjacent wedge body are designed and matched to each other, that when telescoping an adjustable energy absorption by plastic material expansion of the outer wall portion and compression of the inner wall portion, as well as by the friction when telescoping takes place, without causing material breakage of the walls.

The maximum outer diameters of the wedge bodies, measured at their funnel-shaped widened portion, may increase from a first wedge body to a last wedge body. As a result, metal cast components of very different dimensions can be connected to each other. Extreme diameter variations can be compensated by appropriate adaptation pieces between the deformation component and the metal cast components.

Decisive for the function of the deformation component is the interaction of cone angle, wall thickness, load capacity of the predetermined breaking webs and the surface structure. With regard to the cross section of the wedge body a wide variety of variants are possible. In the first place, it is considered expedient if the wedge body has the geometry of a hollow truncated cone, since in this design, the self-centering can be best ensured on a common central longitudinal axis of the wedge body. Deviating geometries, such as, for example, hollow truncated pyramids or hollow truncated wedges are also conceivable. Also wedge body with at least one longitudinally extending guide surface, in particular polygonal wedge body, e.g. Star-shaped wedge bodies are possible. Within certain limits, thereby a mutual rotation of the wedge body when telescoping prevented or specifically promoted in a helical geometry.

The casting component produced by deformation is preferably made of aluminum or an aluminum alloy. In principle, it is also possible within the scope of the invention to use other suitable cast materials.

In order to facilitate the production, the deformation component may have at least one opening on the circumference, so that no hollow casting process is used must be used. The deformation component can therefore have a differently pronounced open cross-section.

The deformation component can be used in addition to the use in the front of the vehicle area for crash-related purposes in structural components or chassis parts in the rear area / rear area.

Figur 1

eine Draufsicht auf ein crashrelevantes Strukturbauteil in Gussbauweise;

Figur 2

im Längsschnitt eine erste Ausführungsform eines Deformationsbauteils und

Figur 3

in schematischer Darstellung den Ablauf des Ineinanderschiebens des Deformationsbauteils bei einem Crash.

The invention will be explained in more detail with reference to an embodiment shown in schematic drawings. Show it:

FIG. 1

a plan view of a Crashrelevantes structural component in a cast construction;

FIG. 2

in longitudinal section a first embodiment of a deformation component and

FIG. 3

a schematic representation of the sequence of the telescoping of the deformation component in a crash.

In FIG. 1 is a schematic structural component 1 shown in a highly simplified design. The structural component 1 comprises two side parts 2 which extend in the direction of travel and are connected to one another via transverse members 3a, 3b extending transversely to the direction of travel. Each side member 2 is divided into three sections: a first metal casting member 4 to which the first cross member 3a is fixed; a subsequent thereto deformation member 5 and finally a second metal casting member 6, on which a transverse member 3b is arranged in this embodiment. The concrete shape of the metal cast components 4, 6 is irrelevant with respect to the inventive concept. The design of the deformation component 5 is important. The deformation components 5 are intended to absorb forces introduced during a crash and to convert them into deformation work. The drawn arrows F illustrate the force application direction, ie the force F is introduced via a bumper arrangement 19 into the front metal casting components 6 and into the deformation components 5, which in turn are supported on the adjacent metal casting component 4. Each side part 2 of the structural component 1 is complete in this embodiment and formed in a cast as a metal casting component. Joining methods between the metal cast components 4, 6 and the deformation component 5 are not required.

FIG. 2 shows in a sectional view of the closer structure of the deformation component 5. The deformation member 5 has in this embodiment, five funnel-shaped wedge body, which are marked with the letters S, A, B, C and E. S stands for a so-called start-wedge body, E stands for an end-stop wedge body. The start wedge body S is integrally connected to an adapter piece 7. The stop wedge body E is also connected to an adapter piece 8. The adapter pieces 7, 8 are configured tubular in this embodiment and have according to the connection diameters of the starting wedge body S and the stop wedge body E thereon matched diameter. The diameter of the adapter piece 7 connected to the starting wedge body S is smaller than the diameter DE of the adapter piece 8 connected to the stop wedge body E. Both the adapter pieces 7, 8 and the wedge bodies S, A, B and E therebetween lie on top a common longitudinal axis LA. It can be seen that the outer diameter DS, DE of the wedge body S, A, B, C, E increases from the starting wedge body S towards the stop wedge body E out. Furthermore, it can be seen that all wedge bodies S, A, B, C, E have matched pitch angles W, so that the mutually facing surfaces 9, 10 of the abutting walls 11, 12 can be brought into abutment flatly and self-locking when plugged into each other. This also contributes to the fact that the mutually facing surfaces 9, 10 of the wedge body at least partially have a surface structure which deforms when pushed into each other by mutual friction, so that the wedge body S, A, B, C, E get stuck together. Each wedge body S, A, B, C, E is connected via a predetermined breaking web 13-16 with the respective subsequent wedge body S, A, B, C, E. The predetermined breaking webs 13-16 are arranged in this embodiment on the stop wedge body E facing funnel-shaped end portion of the respective wedge body S, A, B, C and protrude in a radial plane to the inside, where, for example, the wall 11 of the outer wedge body S with the wall 12 of the engaging in the previous wedge body wedge body A connect. This applies not only to the first two wedge body S, A, but in analogy for the connection of all other wedge body A, B, C, E. The engagement depth T of a wedge body A, B, C, E in the respective preceding wedge body S, A. , B, C is just so large that the wedge body S, A, B, C, E are connected via the intermediate predetermined breaking webs 13-16 and beyond a opposite side guide the wedge body S, A, B, C, E is guaranteed , if a breaking bridge 13 - 16 breaks. Therefore, the engagement depth T is insignificantly greater than twice the width of a predetermined breaking web 13-16.

Out FIG. 2 It can also be seen that the wall thickness D of each wedge body S, A, B, C, E increases in the direction of the respective subsequent wedge body A, B, C, E out. Furthermore, the average wall thickness of the individual wedge bodies S, A, B, C, E increases from the start wedge body S to the stop wedge body E.

The operation of the deformation component will be described below with reference to FIG. 3 explained. FIG. 3 shows the chronological sequence of a crash in five separate illustrations. The uppermost diagram shows the initial state before the action of force in a crash. This representation corresponds to the representation of FIG. 2 , When a certain force level, which is illustrated by the length of the arrow F1, is exceeded, the predetermined breaking web 13 breaks between the starting wedge body S and the adjoining wedge body A. As a result, the starting wedge body S is pushed onto the wedge body A. This causes the wedge body S, A are clamped together. At the same time energy is consumed by the breakage of the predetermined breaking web 13 and the friction occurring between the wedge bodies S, A. At the same time, the outer wall portion 17 of the starting wedge body S is stretched, while the inner wall portion 18, which is enclosed by the wall portion 17, is compressed. The wall sections 17, 18 are pressed into one another so tightly that the wedge body S, A on the one hand safely against each other. On the other hand, a desired Length reduction by the amount L1, that is, the deformation member 5 behaves limited yielding up to a certain level of force.

When the engaging force exceeds a higher predetermined force level (F2), the next breaker bar 14 which connects the wedge body A to the succeeding wedge body B breaks. This can be seen in the third illustration. The deformation component 5 is shortened in this case by the dimension L2. Further energy was absorbed by the breakage of the breakaway web, mutual friction and elongation of the pressed against each wedge body.

If the attacking force F3 becomes even greater (FIG. 3), a further shortening takes place by the dimension L3 or, finally, by the dimension L4 in connection with the force F4 with simultaneously increasing energy absorption. The bottom diagram shows the maximum possible compression of the deformation component 5.

With the crashrelevanten component according to the invention and the integrated deformation element, it is possible to absorb a certain amount of energy by deformation, friction and destruction of the predetermined breaking webs 13, so that a component manufactured by casting behaves impact-soft despite the relatively low ductility caused by production and at the same time a solid composite of each other coupled cast components allows.

Reference numerals:

1 -

structural component

2

Side panel v. 1

3a

cross section

3b-

cross section

4

Metal cast component

5

deformation component

6

Metal cast component

7-

adapter piece

8th-

adapter piece

9-

Surface v. S

10-

Surface v. A

11 -

Wall v. S

12 -

Wall v. A

13 -

Breaking bridge

14 -

Breaking bridge

15 -

Breaking bridge

16 -

Breaking bridge

17 -

Wall section v. S

18 -

Wall section v. A

19 -

bumper assembly

S -

Start wedge body

A -

wedge body

B -

wedge body

C -

wedge body

S -

Stop wedge body

D -

Wall thickness

F1 -

force

F2 -

force

F3 -

force

F4 -

force

L1 -

upsetting

L2 -

upsetting

L3 -

upsetting

L4 -

upsetting

LA -

longitudinal axis

T -

depth of engagement

W -

lead angle

Claims (17)

1. Crash-related component of a vehicle structure or of a chassis of a motor vehicle, with an energy-absorbing deformation component (5) which comprises a plurality of funnel-shaped wedge bodies (S, A, B, C, E) which are arranged in a row and are coordinated with one another in their diameters (DS, DE) via predetermined breaking webs (13-16) with respectively adjacent wedge bodies (S, A, B, C, E) in such a manner that, when a limit load is reached, they can be pushed telescopically one inside another to a limited extent, with the predetermined breaking webs (13, 16) being destroyed, such that the wedge bodies (S, A, B, C, E) which are pushed one inside another are clamped to one another in a self-locking manner, characterized in that the deformation component (5) is a metal cast component which, in a casting process, is connected integrally with an adjacent first metal cast component (4) and with a second metal cast component (6), which components are connected to each other via the deformation component (5), with the mutually facing surfaces (9, 10) of those walls (10, 11) of the wedge bodies (S, A, B, C, E) which come into contact with each other having, at least in some regions, a surface structure which is deformed by mutual friction when said wedge bodies are pushed one inside another.
2. Component according to Claim 1, characterized in that the deformation component (5) is arranged in the longitudinal direction of the vehicle.
3. Component according to Claim 1, characterized in that the deformation component (5) is arranged at a transverse angle with respect to the longitudinal direction of the vehicle.
4. Component according to Claim 3, characterized in that the transverse angle is between 45° and 135° and is in particular 90°.
5. Component according to one of Claims 1 to 4, characterized in that the mutually facing surfaces (9, 10) of the walls (10, 11) which come into contact with each other have mutually coordinated pitch angles (W) which are selected in such a manner that wedge bodies (S, A, B, C, E) which are pushed one inside another are clamped to one another in a self-locking manner.
6. Component according to Claim 1, characterized in that the surface structure is selected in such a manner that wedge bodies (S, A, B, C, E) which are pushed one inside another are clamped to one another.
7. Component according to one of Claims 1 to 6, characterized in that the load-bearing capacity of the predetermined breaking webs (13-16) is selected in such a manner that they break before a selected, maximum tensile or compressive stress, as measured in the circumferential direction, in the wedge body (S, A, B, C, E) is reached.
8. Component according to one of Claims 1 to 7, characterized in that the load-bearing capacity of the predetermined breaking webs (13-16) is selected in such a manner that they break in a manner corresponding to the sequence of the wedge bodies (S, A, B, C, E).
9. Component according to one of Claims 1 to 8, characterized in that the wedge bodies (S, E) which are connected to the metal cast components (4, 6) are connected to the cast components (4, 6) via adaptation elements (7, 8).
10. Component according to one of Claims 1 to 9, characterized in that the wall thickness of a first wedge body (S, A, B, C) is smaller than the wall thickness of the following wedge body (A, B, C, E).
11. Component according to one of Claims 1 to 10, characterized in that the wall thickness (D) of the wedge bodies (S, A, B, C, E) increases in the direction of their funnel-shaped widened portion.
12. Component according to one of Claims 1 to 11, characterized in that the maximum outside diameters (DS, DE) of the wedge bodies (S, A, B, C, E) increase from a first wedge body (S) to a last wedge body (E).
13. Component according to one of Claims 1 to 12, characterized in that the wedge bodies (S, A, B, C, E) have the geometry of a hollow truncated cone.
14. Component according to one of Claims 1 to 12, characterized in that the wedge bodies have the geometry of a hollow truncated pyramid.
15. Component according to one of Claims 1 to 12, characterized in that the wedge bodies have the geometry of a hollow truncated wedge.
16. Component according to one of Claims 1 to 15, characterized in that the metal cast components (4, 6) and the deformation component (5) are produced from an aluminium alloy.
17. Component according to one of Claims 1 to 16, characterized in that the deformation component (5) has at least one opening on the circumference.

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